Datasheet

causes them to do one of two things: rapidly turn on and off as they try to draw more

current from the panel than possible and/or draw much less current than they can, to keep

the voltage from collapsing

Here is a diagram of a single solar cell, in various light conditions (the colored rainbow

lines):

We find these diagrams common but a bit confusing. So we'll show how to use them. Pick

the top red line (maximum light) and start at the very right of the line where it meats the

horizontal scale. This is the current (I) = 0 point. We're drawing no current and the voltage

of the cell is 0.5V. 0.5V is the open circuit voltage. Keep following the graph up and to the

left. As the current draw increases, the voltage drops slightly until we reach the point of

drawing 38mA (0.038A). At this point, the voltage is around 0.4V. Next draw a bit more

current, moving to the left some more and the voltage starts collapsing.We can try to draw

more current but as you can see, drawing even a tiny bit more than 38mA makes the cell

voltage drop to 0V. 38mA is the short circuit current

Depending on the light conditions, the amount of maximum current can range, from 38mA

(red) to 32 mA (orange) down to 5mA (yellow) or even lower. Solar cells can be made larger